Absorption refrigeration apparatus



Dec. 11, 1956 w. G. KOGEL ET AL 2,773,359

ABSORPTION REFRIGERATION APPARATUS Filed Jul 1, 1952 3 Sheets-Sheet 1 24" R if 3 Sheets-Sheet 2 MO V 7 7 7 V H W arra/qwzy 1956 w. G. KOGEL ETAL ABSORPTION REFRIGERATION APPARATUS Filed July 1, 1952 Dec. 11, 1956 1 w. (5. KOGEL ETAL ,7

ABSORPTION REFRIGERATION APPARATUS Filed July 1, 1952 3 Sheets-Sheet 3 United States Patent l:

ABSORPTION REFRIGERATION APPARATUS Wilhelm Georg Kogel, Karl Gunnar Boron, and Axel Harald Ostergren, Stockholm, Sweden, assignors to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporationof Sweden Application July 1, 1952, Serial No. 296,672

Claims priority, application Sweden July 3, 1951 11 Claims. (Cl. 62-103) Our invention relates to absorption refrigeration apparatus of the inert gas type, andmore particularly is concerned with draining and collecting of moisture which is formed on a cooling unit of such apparatus having a plurality of parts or sections which are disposed at difierent levels and operable at different temperatures.

It is an object of our invention to provide an improvement for draining and collecting moisture which is formed on a cooling unit or'evaporator structure of refrigeration apparatus of this kind, particularly to eifect draining and collecting of moisture by flowing moisture from one part of the cooling unit at one level to another part thereof at a lower level in such a manner that the drainage pro visions will take up a minimumamount of usable storage space in the thermally insulated interior of a refrigerator cabinet.

The above and other objects and advantages of the invention will be morefully understood from the following description and accompanying drawings forming a part of this specification, and of which:

Fig. 1 illustrates more or less diagrammatically absorption refrigeration apparatus of the inert gas type to which the invention is applied;

Fig. 2 is a fragmentary vertical sectional view, taken at line 2--2 of Fig. 3 and looking toward the rear of a thermally insulated interior of a refrigerator, illustrating a cooling unit embodying the invention which may be related to other parts of the refrigeration apparatus in the manner diagrammatically shown in Fig. 1;

Fig. 3 is a horizontal sectional view, taken at line 3-3 of Fig. 2, to illustrate the underside of the cooling unit more clearly; and

Figs. 4 and 5 are fragmentary vertical sectional views similar to Fig. 2 illustrating further embodiments of the invention.

In absorption refrigeration apparatus of the inert gas type having a cooling unit or evaporator structure in which parts thereof are adapted to operate at dilferent temperatures, such a cooling unit is generally formed of piping providing several coils which are connected by conduits to other parts of the apparatus for circulation of inert gas therethrough as well as to receive liquid refrigerant. When such an absorption refrigeration apparatus of the inert gas type is employed in the cabinet of a household refrigerator, the coils of the cooling unit and connections thereto are usually positioned in the thermally insulated interior through an opening in a wall of the cabinet which is sealed by a suitable closure member.

Absorption refrigeration apparatus of the inert gas type to which the invention is applicable is more or less diagrammatically shown in Fig. 1. In order to simplify Fig. l, the coils a and 10b of cooling unit or evaporator structure 10 have been illustrated in a more or less conventional manner apart from a household refrigerator. The manner in which the coils of cooling unit 10 may be formed and positioned in the interior of a refrigerator cabinet in accordance with the invention is illustrated in therewith, as by welding, for example.

other figures of the drawings and will be described hereinafter.

The absorption refrigeration apparatus shown in Fig. l is of a uniform pressure type in which an inert gas or auxiliary pressure equalizing fluid is employed. In a system of this type a refrigerant fluid, such as liquid ammonia, for example, is introduced through a conduit 11 into the cooling unit Ill. The refrigerant fluid evaporates and diffuses in the cooling unit 10 into an inert gas, such as hydrogen, for example, to produce refrigeration and abstract heat from the surroundings.

The resulting gas mixture of refrigerant and inert gas flows from the cooling unit through an outer passage 12 of a gas heat exchanger 14 and vertical conduit 15 into an absorber comprising a vessel 16 and a looped coil 17; in the vessel 16 and absorber coil 17 refrigerant vapor is absorbed by a suitable absorbent, such as water, for example, which is introduced into coil 17 through a conduit 18. The hydrogen or inert gas, which is practically insoluble and weak in refrigerant, returns to the cooling unit it) through an inner passage 19 of the gas heat exchanger l-l and a conduit 20.

The circulation of gas in the gas circuit just described is due to the difference in specific weight of the columns of gas rich and weak, respectively, in refrigerant vapor. Since the column of gas rich in refrigerant'vapor and flowing from cooling unit 10 to the absorber coil 17 is heavier than the gas weak in refrigerant and flowing from the absorber coil 17 to the cooling unit 10, a forceis produced or developed within the system for causing circulation of inert gas in the manner described.

From the vessel 16 enriched absorptionliquid flows through a conduit 21 and an inner passage 22 of a liquid heat exchanger into the lower end of a vapor lift tube 23 of a generator or vapor expulsion unit 24. The generator unit 24 comprises a heating flue 25 having the vapor lift tube 23 and a boiler pipe 26 in thermal exchange relation By heating generator unit 24, as by a gas burner 27, for example, liquid from the inner passage 22 of the liquid heat exchanger is raised by vapor lift action through tube 23 into the upper part of the boiler pipe 26. The liberated refrigerant vapor entering boiler pipe 26 from the tube 23, and also vapor expelled fromsolution in the boiler pipe, flows upwardly into an air cooled condenserZS provided with a plurality of heat dissipating members or fins 29. Refrigerant vapor is liquefiedinthe condenser 28 and returns to the cooling unit 10 through the conduit 11 to complete the refrigerating cycle.

The weakened absorptionliquid, from which refrigerant vapor has been expelled, is conducted from boiler pipe 26 through a conduit 30, outer .passage 31 of the liquid heat exchanger and conduit 18 into the upper part of the absorber coil 17. The lower end of the condenser 28 is connected by conduit 32 to the gas circuit, as to the upper part of absorber. coil 17, for example, so that any non-condensable gas which may pass into the condenser can flow to the gas circuit and not be trapped in the condenser.

it will be understood that the cooling unit 10 in Fig. l is diagrammatically shown in the form of a coil and comprises a low emperature evaporator 10a and a higher temperature evaporator 10!: having heat transfer members or fins 33 to provide a relatively extensive heat transfer surface. In Figs. 2 and 3 I have shown a practical form of the evaporator structure or cooling unit 10 of Fig. 1 which is suitable for abstracting heat from the interior of a household refrigerator.

in Figs. 2 and 3, in which parts corresponding to those shown in Fig. l are designed by the same reference numerals, the cooling unit or evaporator structure 10 is horizontally disposed and. includes two looped coils a and 1012, the former serving as the low temperature evaporator section and the latter as the higher temperature evaporator section. The cooling unit 10 is adapted to be positioned in the storage space or thermally insu lated interior of a refrigerator cabinet 34 having top, bottom, rear and lateral side walls. Each of the evaporator sections 10a and 19b is formed of piping which is disposed in a single substantially horizontal plane, the evaporator section 10b being at a slightly lower level than the evaporator section 10a.

In the horizontal cooling unit 10 of Figs. 2 and 3, inert gas weak in refrigerant and flowing from gas heat exchanger 14 is introduced into one end of coil 10a at 35. Liquid refrigerant flows from the condenser 28 through conduit 11 which is also connected at 35 to the looped coil 10a. Inert gas and liquid refrigerant pass from the opposite end of the looped coil 10a through a vertically extending bend 36 to one end of the lower located coil 1012, the opposite end 37 of which is connected to the outer passage 12 of the gas heat exchanger 14 in the manner diagrammatically shown in Fig. l.

The straight portions of the coil sections 10a and 1% are parallel to the lateral side walls 38 and adapted to be at such elevations that liquid refrigerant will flow by gravity from point 35 to the bend 36 of coil section 10a and from such bend to the point 37 of coil section 10b. Hence, liquid refrigerant flows in the same direction and in parallel flow with inert gas in both evaporator sections 10a and 10b.

Since the inert gas flows successively through the evaporator sections 10a and 10b, the gas in section 10a contains a lesser amount of refrigerant vapor than the gas in section 10b. The partial vapor pressure of the refrigerant is a gradient, whereby the temperature of liquid refrigerant is also a gradient, the evaporating temperature of liquid being lower in evaporator section 10a which may be employed for freezing purposes in the cabinet 34. The evaporator section 1%, which is the higher temperature section of the cooling unit or evaporator structure, is utilized to effect cooling of food stored in the thermally insulated interior of cabinet 34.

In the embodiment of Figs. 2 and 3 the evaporator sections 10a and 10b are side by side and extend from one lateral side wall 38 to the opposite side wall of the cabinet 34 and from the rear wall 39 to the front access opening 40 of the cabinet which is adapted to be closed by a suitable door (not shown). A horizontally disposed plate 41 is arranged in thermal exchange relation with the looped coils of both evaporator sections 10a and 10b to provide a shelf for placing matter to be frozen in good thermal contact with the low temperature evaporator section 10a. The plate 41 also serves as a partition to divide the cabinet interior into an upper freezing compartment 42 and a lower food storage compartment 43. As shown, the piping forming the looped coils of the evaporator sections 10a and 10b is fixed in heat conductive relation with the underside of the plate 41 by a number of U-shaped clamps or bracket members 44 having flanges which are secured, as by spot welding, for example, to such plate.

In Fig. 2 it will be seen that a second horizontally disposed plate 45 is provided at the underside of the looped coil of evaporator section 1012. The plate 45 is arranged in good heat conductive connection with evaporator section 10b, as by welding, for example; and a plurality of U-shaped members 46 which are secured to the underside of the plate 45 and correspond to fins 33 in Fig. 1, provide a relatively extensive heat transfer surface to promote cooling of air in the lower food storage compartment 43. The downwardly depending legs or arms of the U-shaped members 46 are essentially parallel to the side walls 38 of the cabinet 34 and form a portion of the higher temperature evaporator section 10b which extends downwardly to a level which is below the low temperature evaporator section 10a. A vessel or tray 47 is positioned in the interior of the cabinet 34 at a region beneath the higher temperature evaporator section 10b. In order to collect moisture which forms on cooling unit 10 and falls from different parts thereof, as during defrosting, for example, a drainage plate 48 is provided at the underside of the cooling unit.

In accordance with our invention the drainage plate 48 is located at the underside of the low temperature evaporator section 10a and all parts thereof are located at a level which is above the extreme bottom edges of the U-shaped members 46 of the higher temperature evaporator section. As seen in Fig. 2, one of the arms or legs of the left-hand member 46 is notched or recessed to receive the lower edge of the baffle plate 48 so that moisture falling and collecting thereon will flow by gravity toward the vicinity of the higher temperature evaporator section 1012. The vessel or tray 47, which may be supported by brackets 49 and 50 fixed to the plate 48 and side wall 38, respectively, in turn is arranged to receive all moisture falling from the higher temperature evaporator section 101) as well as the moisture conducted to such evaporator section by the baffle plate 48. If desired, a suitable connection may be provided for conducting moisture from tray 47 to a collecting vessel at the exterior of the cabinet 34.

In so-called flat evaporators of the kind shown in Figs. 2 and 3 and just described, the low tempefiature evaporator section 10a takes up a minimum amount of space in a vertical direction within the cabinet interior 34 while the higher temperature evaporator section 10b takes up a greater amount of space in a vertical direction because the latter must have the requisite heat transfer surface to promote cooling of air in the food storage space 43. By providing the drainage plate 48 closely adjacent to the low temperature evaporator section 1041 at the underside thereof, and keeping all parts of such drainage plate at a level which is above the extreme bottom portion of the higher temperature evaporator section 10b, a maximum amount of usable storage space is provided in the lower compartment 43 at the region of the drainage plate 48. As best seen in Fig. 2, bottles and other tall items, which may be stored on a shelf below the cooling unit 10, can extend upwardly to a region which is closely adjacent to the underside of drainage plate 48 and at a level well above the extreme bottom edges of the U-shaped members 46.

It will now be understood that the cooling unit or evaporator structure 10 comprises a pair of evaporator sections in which the higher temperature section ltlb takes up less space between the lateral side walls 38 than the overall width of the cooling unit which extends a major portion of the distance between the lateral side walls of the interior of the cabinet 34. In the embodiment of Figs. 2 and 3, the necessity of providing a drip collecting vessel which extends across the entire width of the cabinet interior is avoided, thereby making available a greater amount of storage space for items immediately below the low temperature evaporator section 1.0a. Further, by locating the drainage plate 48 at one side of the higher temperature evaporator section 1012 and conducting moisture on such plate toward the vicinity of the U-shaped members 46, the tray 47, whose width essentially is the same as that of the higher temperature evaporator section 10b, is adequate to collect moisture dripping from the entire cooling unit which extends from one lateral side wall 38 to the opposite sidewall of the cabinet.

In Fig. 4 we have shown the invention embodied in a cooling unit 10' in which the low temperature cooling unit section 10a is at one level and the higher temperature cooling unit section 1011 is at a lower level and located midway between the lateral side walls 38'. The plate 41 is heat conductively connected by U-shaped brackets 44' to the looped coil of evaporator section 10a and extends across the insulated interior of thecabinet 34'. Hence, in Fig. 4 the plate 41' forms the bottom horizontal wall of the freezing compartment 42.

A plurality of fins or plates 46, which are parallel to the rear wall of the interior of cabinet 34, are fixed to the lower looped coil of evaporator section 10b to provide a relatively extensive heat transfer surface for cooling air in the lower or bottom compartment 43'. An inclined drainage plate 48 is positioned at each side of the higher temperature evaporator section 10b. Clamps or brackets 51 are fixed to the plates 48' to form catches which receive the extreme lower edges 52 of downwardly extendingflanges 53 at the extreme outer edges of plate 41. The fins 46 are notched at 54 to receive and hold the lower edge portions 55 of the drainage plates 48. A number of brackets 56 are also fixed to the opposing vertical edges of the fins 46' to provide a suitable support which slidably receives the tray or vessel 47'.

The embodiment of Fig. is generally like the embodiment just described in that a plate 41" heat conductively connected at 44" to the looped coil of low temperature evaporator section 1% extends substantially across the interior of cabinet 34" from one side wall 38" to the opposite side wall. However, Fig. 5 differs from Fig. 4 in that the looped coil of higher temperature evaporator section b" at the lower level is adjacent to one of the side walls 38". In Fig. 5 the plate 45" is heat conductively connected to the looped coil 10b" and U-shaped brackets 46" are fixed to the underside of plate 45" to provide a higher temperature evaporator section having a relatively extensive heat transfer surface. The drainage plate 48" is disposed at one side of the higher temperature evaporator section and held in position beneath a part of the low temperature evaporator section 10a". As shown, the drip plate 48 is provided with clamps or brackets 51" to form catches which receive the lower flanged edges 52" of plate 41". The lower edge of the inclined plate 48" may be secured in any suitable manner to the right-hand U-shaped bracket 46" which will allow moisture flowing downwardly on plate 48 to be conducted into the immediate vicinity of the higher temperature evaporator section 10b and pass into the tray or vessel 47" which is supported by brackets 49" and 50" in the manner shown in Fig. 2. In the embodiments of Figs. 2 and 5 it will be understood that the U-shaped members 45 and 46" may be notched to receive the lower edges of the drainage plates in the same manner the fins 46 are notched in Fig. 4 and described above.

In view of the foregoing, it will now be understood that in each of the embodiments of Figs. 4 and 5, as well as in the first described embodiment of Figs. 2 and 3, the higher temperature cooling section, takes up at least twenty-five percent less space between the lateral side walls of the cabinet than the overall width of the entire cooling unit which extends practically across the entire width of the cabinet interior. Since the looped coil of the low temperature evaporator section in each embodiment is disposed in a single horizontal plane and such looped coil, together with the horizontal plate heat conductively connected thereto, takes up a relatively small space in a vertical direction, a maximum amount of .usable storage space is provided in .eachof the embodiments described and illustrated by locating the drainage plates closely adjacent to the underside of the low temperature evaporator sections.

The higher temperature evaporator sections necessarily must provide a relatively extensive heat transfer surface to effect cooling of air passing in intimate contact with such surface. It is for this reason the members 46, 46 and 46" are provided in the different embodiments, each group of such members forming a packet or bundle of heat transfer elements extending from the rear wall of the interior of the cabinet to a region at the vicinity of I the front access. opening. Since the members 46, 46 and 46" necessarily take up a certain amount of space .in a vertical direction which cannot be avoided, it is distinctly advantageous to provide a low temperature evaporator section of minimum vertical height and employ drainage provisions beneath such evaporator section which affords a maximum amount of usable storage space in the ther mally insulated interior of the refrigerator cabinet.

Modifications of the embodiments of our invention which we have described will occur to those skilled in the art, so that we desire our invention not to be limited to the particular arrangements set forth. Therefore, we intend in the claims to cover all those modifications which do not depart from the spirit and scope of our invention.

What is claimed is; t t l. A refrigerator comprising a cabinet having a thermally insulated interior 'defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas cincuit including a cooling unit having at least two sections disposed in the cabinet interior and comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas at a low average or mean temperature in one. section and at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, means forming a part of said higher temperature cooling unit section which provides a relatively extensive heat transfer surface depending downwardly below said low temperature cooling unit section, said higher temperature cooling unit section taking up at least twenty-five percent less space between said lateral side walls than the overall width of said cooling unit which extends a major portion of the distance between said lateral side walls, structure providingdrip collecting and drainage surface means beneath said low temperature cooling unit section, said structure providing the drainage surface means having all parts thereof within a vertical range whose lower limit is at a level at least as high as the extreme lower portion of said higher temperature cooling unit section, said drainage surface means substantially in its entirety being offset laterally between said side walls with respect to said higher temperature cooling unit section and disposed alongside of the latter, said low and higher temperature cooling unit sections and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature cooling unit section and drip collecting and draincomprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas at a low average or mean temperature in one section and at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, said higher temperature cooling unit section having a relatively extensive heat transfer surface formed by a plurality of heat transfer elements whose lower extremities depend downwardly below said low temperature cooling unit section, said higher temperature cooling unit section takingup at least twenty-five percent less space between said lateral side walls than the overall width of said cooling unit which extends a major portion. of the distance between said lateral side walls, structure providing drip collecting and drainage surface means beneath said low temperature cooling unit section, said structure providing the drainage surface means having all parts thereof within a vertical range whose lower limit is at a 'level at least as high as the lower extremities of said heat transfer elements, said drainage surface means substantially in its entirety being offset laterally between said v side walls with respect to said higher temperature cooling the cabinet interior which extends downwardly from said partition.

' 3. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including a cooling unit having at least two sections disposed in the cabinet interior and comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas at a low average or mean temperature in one section which is below the freezing temperature of water and at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, said low temperature cooling unit section comprising an active portion of said piping and a horizontal member in good thermal relation therewith which defines the bottom of a frozen food and ice freezing compartment, means comprising said higher temperature cooling unit section for cooling that portion of the cabinet interior beneath said horizontal member, said higher temperature cooling unit section comprising an active portion of said piping and vertically disposed heat transfer members in good'thermal relation therewith, structure providing drip collecting and drainage surface means under said horizontal member and piping of said low temperature cooling unit section, said structure providing the drainage surface means having all parts thereof within a vertical range whose lower limit is at a level at least as high as the lower extremities of said vertically disposed heat transfer elements, said drainage surface means substantially in its entirety being offset laterally between said side walls with respect to said higher temperature cooling unit section and disposed alongside of the latter, said horizontal'mernber and low and higher temperature cooling unit sections and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature cooling unit section and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of the cabinet interior which extends downwardly from said partition.

'4. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including a cooling uni-t having at least two sections disposed in the cabinet interior and comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas at a low average or mean temperature in one section and l at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, said cooling unit sections including active portions of said piping, each of the aforesaid active portions having piping disposed essentially in a horizontal plane, said higher temperature cooling unit section taking up at least twenty-five percent less space between said lateral side walls than the overall width of said cooling unit which extends a major portion of the distance between said lateral side wall structure providing drip collecting and drainage surface means beneath said low .tempera-ture cooling unit section, the drainage surface means directing moisture collecting thereon toward the immediate vicinity of said higher temperature cooling unit 8 section, said "structure providing the drainage surface means having all parts thereof within a'vertical range whose lower limit is at a level at least as high as the extreme lower portion of said higher temperature cooling unit section, said drainage surface means substantially in its entirety being offset laterally between said side walls with respect to said higher temperature cooling unit section and disposed alongside of the latter, means for collecting moisture from both of said cooling unit sections including a vessel which is supported beneath said higher temperature cooling unit section, such vessel extending between said lateral side walls for a distance which essentially'is the same as that of said higher temperature cooling unit section, said low and higher temperature cooling unit sections and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature cooling unit section and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of the cabinet interior which extends downwardly from said partition.

5. Apparatus as set forth in claim 4 in which said low and higher temperature cooling unit sections are disposed alongside one another and the overall width of said cooling unit comprises substantially the entire width of both of said low and higher temperature cooling unit sections.

6. Apparatus as set forth in claim 4 in which the width of said low temperature cooling unit section defines the overall width of said cooling unit and all of said higher temperature cooling unit section is disposed beneath a part of said low temperature cooling unit section.

7. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including a cooling unit having at least two sections disposed in' the cabinet interior and comprising piping having active portions in which liquid refrigerant evaporates in the'presence of an inert gas at a low average or mean temperature in one section which is below the freezing temperature of water and at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, said low temperature cooling unit section comprising an active portion of said piping disposed essentially in a horizontal plane at a first level and a horizontal member in good thermal relation therewith, means comprising said higher temperature cooling unit section for cooling that part of the cabinet interior beneath said horizontal member, said higher temperature cooling unit section comprising an active portion of said piping disposed essentially in a horizontal. plane at a second level below said first level and vertically disposed heat transfer members in good thermal relation therewith, said higher temperature cooling unit section taking up at least twenty-five percent less space between the lateral side walls than the overall width of said cooling unit which extend from the vicinity of one lateral side wall to the vicinity of the opposite lateral side wall, structure providing drip collecting and drainage surface means under the partition and piping of said low temperature cooling unit section, said structure providingthe drainage surface means having all parts thereof within a vertical range whose lower limit is at a level at least as high as the lower extremities of said vertically' disposed heat transfer elements, said drainage surface rneans substantially in its entirety being offset laterally between said side walls with respect to said higher temperature cooling unit section and disposed alongside of the latter, said horizontal member and low and higher temperature cooling unit sections and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature coolingunit section and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of theca-binet interior which extends downwardly from said partition.

8. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including a cooling unit having at least two sections disposed in the cabinet interior and comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas at a low average or mean temperature in one section which is below the freezing temperature of water and at a higher average or mean temperature in another section, means for flowing liquid refrigerant by gravity through said low and higher temperature cooling unit sections, respectively, a horizontally disposed member which is heat conduct-ively connected to said low temperature cooling unit section, the piping of said low temperature cooling unit section being at one level and the piping of said higher temperature cooling unit section being spaced from both of said lateral side walls and taking up less space than the overall width of said cooling unit which extends a major portion of the distance between said lateral side walls, structure providing drip collecting and drainage surface means underneath said low temperature cooling unit section at each side of said higher temperature cooling unit section, the drainage surface means providing for moisture collecting thereon paths of flow toward the immediate vicinity of said higher temperature cooling unit section at opposing lateral side regions thereof, said structure providing the drainage surface means having all parts thereof within a vertical range whose lower limit is at a level at least as high as the extreme lower portion of said higher temperature cooling unit section, said horizontally disposed member and low and higher temperature cooling unit sections and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature cooling unit section and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of the cabinet interior which extends downwardly from said partition.

9. Apparatus as set forth in claim 8 which includes means for collecting moisture from both said low and higher temperature cooling unit sections, said moisture collecting means comprising a vessel which is supported beneath said higher temperature cooling unit section, said vessel normally being spaced from both of said lateral side walls and occupying a space therebetween which is essentially the same as the width of said higher temperature cooling unit section.

10. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including evaporator structure disposed in the cabinet interior comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas, said evaporator structure comprising low and higher temperature evaporator members including active portions of said piping, each of the aforesaid active portions having piping disposed in a horizontal plane, a horizontally disposed member which is heat conductively connected to both of said evaporator members, the active portion of the piping of said low temperature evaporator member being disposed at one level and the active portion of the piping of said higher temperature evaporator member being disposed at a lower level, said higher temperature evaporator member taking up at least twenty-five percent less space between the lateral side walls than the overall width of said evaporator structure which extends from the vicinity of one lateral side wall to the vicinity of the opposite lateral side wall, and provisions providing drip collecting and drainage surface means at the underside of said low temperature evaporator member, said provisions providing drain age surface means having all parts thereof within a vertical range whose lower limit is at least as high as the extreme bottom part of said higher temperature evaporator member, said drainage surface means substantially in its entirety being offset laterally between said side walls with respect to said higher temperature evaporator member and disposed alongside of the latter, said horizontally disposed member and low and higher temperature evaporator members and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature evaporator member and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of the cabinet interior which extends downwardly from said partition.

11. A refrigerator comprising a cabinet having a thermally insulated interior defined by top, bottom, rear and lateral side walls, an absorption refrigeration system comprising a gas circuit including evaporator structure disposed in the cabinet interior comprising piping having active portions in which liquid refrigerant evaporates in the presence of an inert gas, said evaporator structure comprising low and higher temperature evaporator members including active portions of said piping, each of the aforesaid active portions having piping disposed in a horizontal plane, a horizontally disposed member which is heat conductively connected to said low temperature evaporator member, the active portion of the piping of said higher temperature evaporator member being disposed beneath the active portion of the piping of said low temperature evaporator member, said higher temperature evaporator member taking up at least twenty-five percent less space between the lateral side walls than the overall Width of said evaporatorstructure which extends from the vicinity of one lateral side wall to the vicinity of the opposite lateral side wall, and provisions providing drip collecting and drainage surface means at the underside of said low temperature evaporator member, said provisions providing the drainage surface means having all parts thereof within a vertical range whose lower limit is at a level at least as high as the extreme bottom part of said higher temperature evaporator member, said drainage surface means substantially in its entirety being offset laterally between said side walls with respect to said higher temperature evaporator member and disposed alongside of the latter, said horizontally disposed member and low and higher temperature evaporator members and drip collecting and drainage surface means forming a partition in the cabinet interior, and said higher temperature evaporator member and drip collecting and drainage surface means, respectively, forming ceiling areas of that part of the cabinet interior which extends downwardly from said partition.

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